In the automotive industry, for example, linear position sensors which operate using magnetic transducers and magnetic sensors are widespread. A plurality of permanent magnets having precisely specified pole transitions usually faces a sensor array (usually two-dimensional), the magnetic transducer being displaceable in one direction parallel to the sensors. The sensors are usually Hall sensors and detect a pole transition of the magnetic field permeating the sensors. Since the pole transition of the magnetic transducer configuration corresponds to a defined geometric mark, the position of the magnetic transducer configuration in relation to the sensor array is therefore detectable.
Strip-shaped permanent magnets situated side by side for space-saving reasons are generally used as magnetic transducers, resulting in a mutual influence. The permanent magnet elements are magnetized in the longitudinal direction, the pole transitions being offset from one another so that a magnetized section of a neighboring permanent magnet element is situated at the height of a pole transition of a permanent magnet element, thereby laterally influencing the course of the neighboring pole transition. Since the influence of neighboring magnet elements decreases with distance, the pole transition does not run exactly perpendicularly in the longitudinal course but instead is distorted due to neighboring fields. A further distortion occurs due to the magnetic guidance by the magnetic material, this guidance being stronger at the center of the cross section than at the edge.
The result is therefore not an accurately defined pole transition, the positioning of the magnetic sensor across the longitudinal axis in particular having a strong influence on in which position the pole transition is actually detected.
Conventionally, this inaccuracy may be compensated by an additional complex calibration step after installation of the position sensor or to discard position sensors outside of a tolerance range based on an accurate subsequent measurement. A greater distance between the permanent magnet elements would reduce the distortion but is impossible in numerous applications having a small installation space and a high integration density.